Endoscopic biopsy needle with coil sheath

ABSTRACT

A notched tissue-collection needle configured similarly to a fine-needle-aspiration needle is provided with a cutting edge disposed in the notch and configured to excise tissue into the notch for collection. A stylet may be provided through a lumen of the needle during introduction into a patient body. The needle may be provided with echogenicity-enhancing features. A coated-coiled-wire sheath through which the needle is slidably disposed includes an overcoating that is thicker along a distal length and thinner along a mid-section length intermediate the proximal and distal lengths, and may include another thicker proximal-most portion adjacent the handle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 USC §120 to co-pending U.S.patent application Ser. No. 14/195,333, filed Mar. 3, 2014, which claimspriority under 35 USC §120 to PCT App. No. PCT/US/2014/013552, filedJan. 29, 2014, both of which applications claim priority under 35 USC§119(e) to U.S. provisional application Ser. No. 61/772,831, filed Mar.5, 2013, where each of the foregoing applications is incorporated byreference herein in its entirety.

TECHNICAL FIELD

The present embodiments relate generally to endoscopic surgical devices.More particularly, the embodiments described herein pertains to asheathed biopsy needle configured for use during minimally-invasiveprocedures such as endoscopic procedures.

BACKGROUND

Fine needle aspiration (FNA) is a diagnostic biopsy procedure used toobtain a sample from a target site in a patient body. A fine needle(e.g., 19-gauge to 25-gauge) is directed to a target site, and suctionis applied to the proximal end of a lumen of the needle to aspiratecells through its distal end. The procedure typically is far lessinvasive than other biopsy techniques, whether performed percutaneously(e.g., to sample a suspected breast tumor or subcutaneous lesion) orendoscopically (e.g., to sample a suspected cholangiocarcinoma via aduodenoscope). Moreover, advances in endoscopic ultrasound (EUS)technology have helped physicians and patients by providing enhancedability of a physician to visualize a biopsy needle to obtain a sampleof material from a target site without requiring an open incision or useof large-bore needles and/or laparoscopic trocars.

Current FNA techniques typically obtain only a small number of cellsuseful for diagnostic evaluation. As a result, this technique includes arisk of false negatives where the few cells obtained in a sample do notaccurately represent the presence of a tumor or other disease condition.The small sample size may also limit the diagnostic value of theprocedure if the cells obtained are sufficiently few in number orsufficiently damaged during collection that they do not enable adefinitive diagnosis. Accordingly it would be advantageous to provide aneedle useful for EUS and/or percutaneous FNB (fine needle biopsy) thatcan obtain a larger sample size (e.g., a larger number of cells in thesample or a “core” comprising intact adjacent cells held together insimilar form to their native location, suitable for histologicalanalysis) without requiring a larger-gauge needle or requiring multiplepasses of the needle to reliably obtain a diagnostically efficacioussample with regard to the number and integrity of the cells in thesample. It would also be advantageous for the needle to be constructedin a manner providing for efficient operation through an endoscope suchas a side-viewing gastric endoscope (also known as a duodenoscope),including ready navigation through the curvature(s) commonly required inusing such an endoscope with a minimum of time and manipulationrequired.

BRIEF SUMMARY

Embodiments of needles disclosed here address these problems of thecurrent technology and present advantages over existing needles withregard to both structure and methods. In one aspect a tissue-samplingneedle device may include an elongate tubular cannula with a cannulawall defining a cannula lumen, where the cannula lumen extendslongitudinally through the cannula. The cannula may include a distalbeveled end with a long side and a short side and a notch through thecannula wall that is open to the cannula lumen. The notch is disposedproximally adjacent to the beveled distal cannula end and is generallycentered in longitudinal alignment with the long beveled end side andopposite the short beveled end side. Also, the notch may include adistal lip defined by a portion of the cannula wall, the distal lipbeing configured to extend proximally from a distal-most end of thenotch such that a central distal lip portion is disposed proximal of lipend portions that are continuous with generally longitudinal lateralsides of the notch, and to include a proximal-facing cutting edge.

In another aspect, a notched aspiration biopsy needle disclosed hereinmay include a flexible elongate tubular cannula, preferably sized nolarger than 19-gauge, with a cannula wall defining a cannula lumenconfigured to communicate with a proximal source of suction. The cannulalumen extends longitudinally through the cannula, a distal beveled endof the cannula including a long side and a short side, and the structureincludes a notch through the cannula wall, open to the cannula lumen.The notch is disposed proximally adjacent to the beveled distal cannulaend and is generally centered in longitudinal alignment with the longbeveled end side and opposite the short beveled end side, and the notchincludes a cutting edge defined by a distal-facing portion of thecannula wall. A delivery sheath may also be included, where the deliverysheath is constructed including a coiled coated-wire tubular sheath bodywith an outer polymer coating. The coiled coated-wire tubular sheathbody may include a stainless steel wire coated with PTFE or anotherlubricious polymer where the coated wire is coiled to form a generallypatent tubular body. The sheath body may further be coated along itsouter surface with an extruded polymeric overcoating such as nylon. Adistalmost length of the polymeric overcoating may be provided at agreater thickness than a proximal length of the polymeric overcoatingsuch that a distal sheath length has a larger outer diameter and greatercolumnar strength than a more proximal sheath length.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to assist the understanding of embodiments of the invention,reference will now be made to the appended drawings, which are notnecessarily drawn to scale or proportion, and in which like referencenumerals generally refer to like elements. The drawings are exemplaryonly, and should not be construed as limiting the invention unlessspecifically described as so doing.

FIG. 1 shows an embodiment of a biopsy needle assembly;

FIGS. 2A-2D show different views of a tissue-sampling needle deviceembodiment;

FIG. 3 shows a distal portion of the biopsy needle assembly of FIG. 1with the needle extended from the sheath, and the sheath partially shownin longitudinal section; and

FIG. 3A shows a distal portion of a biopsy needle assembly with theneedle extended from the sheath including a plurality of thickerovercoating lengths (outer diameter differences shown slightlyexaggerated and not necessarily to scale in FIGS. 3-3A).

DETAILED DESCRIPTION

As used herein, the term “proximal” refers to the handle-end of a deviceheld by a user, and the term “distal” refers to the opposite end. Theterm “surgical visualization device” refers to endoscopes including CCD,ultrasound, fiber optic, and CMOS devices, as well as other devices usedfor visualizing an internal portion of a patient body such as, forexample, a laparoscope or bronchoscope.

One embodiment of a tissue-sampling needle device is described withreference to FIG. 1, which shows a biopsy needle assembly 160. Thebiopsy needle assembly 160 includes a handle 162, from which a sheath170 extends distally. A needle device 200 is configured to be slidablydisposed longitudinally through the sheath 170 and is shown anddiscussed below in greater detail with reference to FIGS. 2A-2D and FIG.3. The structure of one embodiment of the sheath 170 is discussed ingreater detail with reference to FIG. 3. In the embodiment of FIG. 1,the handle 162 includes a needle-moving element 164 and a sheath-movingelement 166 and lockable stops with numerical indicia foruser-controlled manipulation with respect to specified distances oflongitudinal movement of each. In certain embodiments, the handle may beconfigured in a manner disclosed in U.S. Pat. No. 6,976,955 to Hardin,et al., which is incorporated herein by reference.

Detailed views of an embodiment of the needle portion of the biopsyneedle assembly 160 are depicted in FIGS. 2A-2D, which show atissue-sampling needle device 200 (which includes the needle cannula andstylet). As shown in the side plan view of FIG. 2A, the device includesa proximal handle or hub 202 from which an elongate tubular cannula 204extends distally. In certain preferred embodiments, the hub 202 will bemounted or otherwise incorporated into a handle such as the handle 162shown in FIG. 1. The cannula 204 includes a cannula wall 206 thatdefines a cannula lumen 208. A distal end 210 of the cannula 204 islancet-beveled, including a long side 210 a substantially parallel withthe central longitudinal axis of the cannula 204 and extending to itsdistal-most tip end. A short side 210 b of the beveled distal end 210 isopposite the long end 210 a. A detailed illustration of the distal end210 is shown in the top plan view of FIG. 2B, which (like FIGS. 2C-2D)shows only a distal end length of the device 200 shown in FIG. 2A. Otherembodiments may include a double bevel, where one beveled surface isopposite the notch, or single or double bevels that are at leastpartially transverse relative to the notch 220.

As shown in the side plan view of FIGS. 2A and 2C, and in theperspective view of FIG. 2D, a notch 220 is disposed proximally adjacentto the beveled distal cannula end 210 and is generally centered inlongitudinal alignment with the long beveled end side 210 a and oppositethe short beveled end side 210 b. In preferred embodiments, the notch220 is generally arcuate, defined on its distal side by a parabolic edge222 extending along generally longitudinal, but somewhat curved lateralnotch sides 224. The proximal edge 224 of the notch 220 preferably isformed as generally parabolic lip that joins the distal edge 222 at apair of lip end portions 226 that preferably provide a curved transitionbetween the distal lateral and proximal edges 222, 224. The radiused lipend portions 226 preferably are configured to provide stress reliefwithin the cannula structure. A central proximal lip portion 225 of theproximal edge 224 preferably forms a distal-facing cutting edge. Inpreferred embodiments, the notch will occupy less than about one-halfthe circumference of the cannula 204 at the broadest point of the notch.Inclusion of the bevel illustrated in FIG. 2C may provide advantages forsuccessful sample collection. Specifically, contact of the bevel faceagainst tissue may create a slight bias/pressure toward the notch thatwill help tissue to be pulled/captured into the notch when the stylet(described below) is withdrawn, including that contact pressure on thenotch side of the shaft surface may be slightly greater than on theexterior surface immediately opposite the notch. The cannula 204 has aconsistent or at least substantially consistent outer diameter along atleast its distal length from distal of the notch 220, across the notch,and proximal of the notch.

An elongate stylet 230 may be disposed removably through the cannulalumen 208. In preferred embodiments the stylet 230 will occupysubstantially or nearly an entire cross-sectional area of at least alengthwise portion of the cannula lumen 208. And, as shown in FIG. 2C, adistal end 232 of the stylet 230 may be rounded and dimensioned not toextend out of the distal beveled cannula end 210. This construction willprovide enhanced support for the cannula (particularly during navigationto a target site). It should be appreciated that a beveled stylet end orother stylet end configuration may be practiced within the scope of thepresent invention and, in the case of a beveled-end stylet, may providea generally solid cutting and/or tissue-penetrating distal tip endformed by matching bevels of the stylet 230 and cannula 204. Aproximal-end stylet cap 234 attached to the stylet 230 is shown with aprotruding tab 235 configured to align with the short side 210 b of thebeveled distal cannula end 210. In a needle assembly like the needleassembly 160 of FIG. 1, this feature may lock into a corresponding notchon the handle 162 and be used by treating personnel to determine therotational orientation of the distal needle end region including thenotch 220 and distal bevel.

The needle embodiment is shown here with an open distal end, but, incertain embodiments, the distal beveled needle end may be closed, suchthat the lumen 208 extending longitudinally through the cannulaterminates within the cannula 204. In these embodiments, a stylet may bereinserted into the needle lumen after the sample has been excised andcaptured through the notch into the needle lumen. In such acircumstance, the stylet may be extended distally to cover the opennotch (thereby preventing contamination of the sample by inadvertentcollection of cells along the needle track during withdrawal of theneedle), but leaving room in a closed needle lumen portion for thesample to remain intact between the notch and a closed distal end in anembodiment where the needle lumen is closed at the distal end.

In one exemplary embodiment of the needle portion of the biopsy needleassembly, the cannula 204 may be constructed as a 20-gauge needle madeof 304 stainless steel, with an inner diameter of about 0.9 mm (about0.03 inches) and an outer diameter of about 0.91 mm (about 0.036inches). In this embodiment, the notch 220 may be circumferentiallylocated opposite and proximal of a distal bevel that is at about a 18.3°angle (±about 5°) relative to the short side such that a proximal-mostend of the notch 220 (defined by the curved lip end portion 226) isabout 7.1 mm (about 0.28 inches) longitudinally proximal of thedistal-most tip end of the cannula 204. In this embodiment, thelongitudinal distance between the distal-most notch edge 222 and thedistal-most portion of the rounded proximal cutting lip 225 will beabout 3 mm (about 0.12 inches). The distal -most portion of the proximallip 225 will be about 0.56 mm (about 0.022 inches) from theproximal-most end of the notch 220, which will be defined by a curvedlip end portion 226, including a radius of curvature of about 0.05 mm(0.002 inches), joining the proximal edge 224 with the distal edge 222.A beveled or round-tipped NiTi stylet 230 may be disposedslidably/removably through the cannula lumen. It should be appreciatedthat, while a needle not larger than a 19-gauge needle is preferred,smaller gauge needles such as—for example—22-gauge and 25-gauge needlesmay be practiced within the scope of the present disclosure (although,it will be appreciated that their absolute dimensions will vary fromthose disclosed for the 20-gauge example). The notch may be orientedwith a proximal-facing cutting lip (e.g., such as is disclosed inco-owned U.S. Pat. Publ. 2012/0253228 to Schembre et al., which isincorporated herein by reference in its entirety).

As shown in FIG. 2A, some embodiments of the cannula 204 may includesurface features 240 configured to enhance echogenicity, therebyproviding an improved ability to navigate the device during an EUSprocedure. The surface features 240 are shown here as dimples on anexterior surface of the cannula 204, but may alternatively be embodiedas grooves or other regular or irregular features on an external orinternal surface. Embedded echogenic features such as bubbles, voids, orpieces of echo-contrasting materials may also be used within the scopeof the present invention. Those of skill in the art will appreciate thatmany currently-known and/or future-developed echogenicity-enhancingmeans may be used within the scope of the present invention. As usedherein, the terms echogenic and echogenicity-enhancing are used to referto structural features that increase the reflectivity of ultrasoundwaves used during ultrasound visualization of a device, with theincrease being over the typical ultrasound reflectivity/visualizabilityof a device lacking the features described.

The echogenic features 240 may extend distally across the cannulasurface radially opposite space occupied by the notch 220. It ispreferable that echogenicity-enhancing features be disposed at aspecified predetermined distance from the distal-most tip end of thecannula 204. Although the echogenic features 240 are shown at a distancefrom the notch 220, a cannula according to the present embodiments maybe constructed with those echogenic features disposed flush up to themargins of the notch, including being immediately proximally, distally,and/or longitudinally adjacent to the notch. The stylet 230 may includeechogenicity-enhancing features instead of or in addition to those thatmay be disposed on the cannula 204.

FIG. 3 shows a distal portion of the biopsy needle assembly of FIG. 1with the needle 204 extended from the sheath, and the sheath 170partially shown in longitudinal section. A call-out/detail portion showsthe longitudinal cross-sectional view in greater/magnified detail. Thesheath 170 may be constructed as including a coiled coated-wire tubedefining a longitudinal sheath lumen 172. The needle cannula 204 isslidably disposed through the sheath lumen 172, and the sheath 170 isfixed to a portion of the handle 162. At least a distal length of thesheath 170 extending from a distal sheath end will include the coiledcoated-wire tube construction, and the entire sheath may be soconstructed. In one embodiment, the coiled coated-wire tube constructionincludes stainless steel wire 174 (such as, for example, 304 stainlesssteel) that is coated with a lubricious polymer 176 (such as, forexample, PTFE, whether alone or in combination with other material(s))and coiled to form a wire tube of substantially consistent inner andouter diameter. This construction will provide desirable columnarsupport and protection for the needle cannula 204 and for the interiorsurface of an endoscope working channel through which the device is tobe operated.

In some embodiments, the sheath 170 may also include a polymericovercoating 180 (illustrated as a substantially transparent overcoatingin FIGS. 3-3A, although actual embodiments may be opaque). In onedesirable embodiment, nylon is extruded over the tube body. Onedesirable nylon polymer is commercially available as AESNO MED™ fromArkema of King of Prussia, Pa. Other suitable materials may includeother long-chain aliphatic polyamides and/or polyimide (e.g., availableas Grilamid® from EMS-GRIVORY of Domat/Ems, Switzerland). Theovercoating 180 will provide additional strength and integrity for thetube body. The distal end of the device 100 may be subjected to rathersevere curvature(s) when directed through an endoscope working channelto a target site. Such severe curvature exerts forces on the needlecannula 204 that theoretically could increase a risk of undesirablebending and/or kinking, particularly in the region of the notch 220, andit would be desirable to avoid any such deformation of the cannula.

In certain embodiments, a thicker extrusion (or otherwise-applied)overcoating may be provided along a proximal region 170 a of the sheath170 (immediately adjacent the handle 162), and it may extend into thesheath-adjusting handle element 166. This thicker “bump region” of theproximal sheath 170 a (thicker than the mid-section region 170/182,where 170 a corresponds to 186 b of FIG. 3A) will provide increasedsupport in the transition region of the sheath out of the handle, whichcan be prone to kinking. The additional columnar support will increasethe bend radius and reduce the risk of kinking (including strain relief)while not adding additional components or adversely affecting thefunctional efficacy of the sheath extension/retraction. The scale ofFIG. 1 does not clearly indicate the different sheath outer diameters,but those of skill in the art will understand the structure withreference to this description and the similarly-structuredincreased-diameter distal length(s) described herein.

In one example, a surgical visualization device such as an endoscopicultrasound (EUS) duodenoscope may be used to identify a target area forbiopsy in or near the pancreas head of a patient. The curvaturetypically required by the scope to visualize this region is so tight asnot to allow passage through the scope's working channel of a biopsyneedle (either absolutely, or without risking damage to the needle). Insuch cases, the scope is typically used to identify the region via EUS,including positional maneuvering to get the distal end of the workingchannel in place to access the target, whereupon the scope must berelaxed at least somewhat to allow the biopsy needle to be directedslight out of the working channel. Thereafter, the target must bere-acquired before the biopsy needle can be used for collectiontherefrom. The presently disclosed system advantageously provides anovel sheath with sufficient flexibility and needle-support that theintermediate relaxation/re-targeting step is not needed, and the cannula204, including the notch 220 have columnar support sufficient tominimize the likelihood of undesired deformation. To the extent thatrelaxation of the scope may be needed during use of presently-disclosedembodiments, it will generally be less than required by priorconfigurations, and significantly less than traditional metal-body andother endoscopy needles.

The polymeric overcoating 180 will limit “gapping” between adjacentcoils of the sheath's tube body during manipulation, includingtorqueing, curving, etc. When the notch 220 is within the sheath lumen,this will help prevent the lip 225 from catching on a coil or gapbetween adjacent coils. It will also limit—but not unduly—the curvatureof the sheath. In one preferred embodiment, shown in FIG. 3, thepolymeric overcoating 180 includes a thicker extruded portion 186 alonga distalmost length of the sheath 170, which overlies the notch 220 andwill provide it with support as it is navigated, particularly across thetight curve/turn of exiting an endoscope while being torqued by theendoscope's elevator. This will prevent the needle from deforming oreven kinking along the notch region—while preserving the large notchopening that is configured for and provides superior sample-collectionof FNA-collected cells and/or FNB-collected histological-grade tissuecores. As shown in FIG. 3, a proximal length 182 includes a thinnerovercoating that ramps along a smooth, non-stepped transition length 184to a larger outer diameter distal length 186, where the distalface/terminus of the sheath may be rounded/polished to present a surfacethat is smoothly navigable through a working channel of a surgicalvisualization device. In certain embodiments, the overcoating 180 mayinclude a polished radiused transition from the sheath outer diameter tothe sheath lumen. For example, in certain embodiments, the overcoating180 may extend beyond the distal end of the coated coil 174 by about 0.5mm (that is, about 0.1 mm to about 0.9 mm), with a polished radiusedtransition to the sheath lumen 172.

Those of skill in the art will appreciate, with reference to the presentteaching, that this structure provides for increased columnar strengthof the sheath along a distalmost length that overlies the needle notch220 when it is not extended out of the sheath. This thicker/larger outerdiameter length may extend about 5 mm to about 90 mm, preferably 10 mmto about 50 mm or more from the distal sheath end. In addition toincreased columnar strength, this larger-OD length 186 will limit theamount by which a scope elevator can bend/torque the sheath 170 byimposing a larger bend radius, which will further protect the integrityand functionality of the needle body 204. In other words, the largerouter diameter distal sheath length preferably is effective to limitendoscope elevator deflection of the sheath to less than the degree ofdeflection allowed by the smaller outer diameter distal sheath length.The larger-OD distal length may extend about 5% to about 50% of thesheath length from its distal end, often between about 5% to about 30%.That thicker-OD distal length may be about 3% to about 50%, preferablyabout 5% to about 20%, and more preferably about 9% to about 17%, largerin diameter than the thinner-OD proximal length of sheath overcoating.

Certain preferred embodiments may include at least one, and may includea plurality of larger-OD and thinner-OD sheath-thickness overcoatingregions, but otherwise being like or identical to the embodimentsdescribed above. As shown in FIG. 3A, an intermediate (mid-section)length 182 of a needle sheath assembly 160 a includes a thinnerovercoating that ramps along smooth, non-stepped transition lengths 184a, 184 b to (respectively) a larger outer diameter more-distal length186 a and a larger outer diameter less-distal length 186 b (where, asnoted above and implicit in the drawing figures, the drawing is not toscale with regard to relative thickness and to the relative length of182, and where 186 b may correspond to proximal-most length 170 a).

In a sheath embodiment configured for use with the illustrative exampleof a 20-gauge needle described above, the coiled coated-wire tubeconstruction exclusive of the overcoating 180 may have an outer diameterof about 2.18 mm (about 0.086 inches). The overcoated outer diameter maybe about 2.2 mm (about 0.09 inches) along the proximal/smaller-diameterlength and about 2.5 mm (about 0.1 inches) along thedistal/larger-diameter length. In a slightly varied embodiment, theovercoated outer diameter may be about 2.34 mm (about 0.092 inches)along the proximal/smaller diameter length and about 2.61 mm (about0.103 inches) along the proximal/smaller diameter length. The innerdiameter, preferably effectively lined by the lubricious coating 176 ofthe wire 174, may be about 1.3 mm (about 0.05 inches). The absolute andrelative sizes may vary in other embodiments from the representativeembodiments described here.

At the same time, the construction disclosed here provides superiorflexibility over other known sheath designs (e.g., PEEK sheaths) toprovide the desired ease of access without significant, if any, scopere-positioning. This includes that some procedures may be completedwithout relaxing/re-torqueing and/or other significant re-positioning ofthe scope after initial targeting and placement, in contrast with pastneedle designs that could not be advanced through a highly-torqued scopeand/or across an extended elevator without configuration changes orincreased risk of damage to the needle. This structural and functionaladvantage will help reduce procedure time, and will enhance thefunctional efficiency of endoscopic biopsy configured to obtainhistological samples. In a typical deployment, the distal needle endwill be nearly aligned with, or will be just proximal of the distalsheath end, which will provide the benefits described here during use.

Those of skill in the art will appreciate with reference to the presentdisclosure by way of further teaching in addition to the state of theart that a method of tissue collection may be implemented using theassembly 160 described above. The needle cannula 204, with the stylet230 disposed therein, may directed via the working channel of a surgicalvisualization device (e.g., an EUS duodenoscope) into a target site tobe sampled (e.g., a suspected tumor mass in the head of a patient'spancreas). The stylet 230 may be withdrawn and suction applied to theneedle cannula lumen 208. One or more of suction, rotary manipulation,and/or longitudinal manipulation of the needle cannula 204 will excise(e.g., via the cutting lip 224) and capture tissue, which preferablywill include sufficiently intact samples for histology, from the targetsite through the notch 220 into the lumen 208.

The sample obtained preferably will include a desirable number of intactcells, preferably more intact cells than are ordinarily obtained using anon-notched FNA biopsy needle (“more” indicating both a greater numberand a higher degree of tissue/cell integrity within the sampleobtained). It has been found that histological-grade FNB samples may beobtained in this manner, which may be preferred for certain diagnosticpurposes over the cytological-grade samples typically obtained throughFNA. The needle may then be withdrawn from the patient's body.

In one preferred embodiment, during introduction of the device into apatient body, the cannula 204 will be directed through the workingchannel of a peroral endoscope such as a duodenoscope into a patient'sbody. It is then navigated (under ultrasound visualization ifechogenicity-enhancing features are provided, as in the embodiment shownin FIGS. 1-3) into a target site. In other embodiments, the device maybe introduced through other access means known in the art includingpercutaneous means such as direct insertion of the needle cannulathrough a patient's skin or insertion through a trocar, sheath, or otheraccess device (with or without endoscopic or ultrasound visualization),all within the scope of the present invention. It should also beappreciated that an outer sheath may be disposed slidably along theexterior of the cannula 204 and the needle retracted thereinto (and/orthe sheath distally advanced) so that the sheath is disposed over thenotch 220 after the sample is collected. This configuration, which maybe practiced within the scope of the present invention, may lessen thelikelihood that the sample collected will become lost or contaminatedduring needle withdrawal.

The needle device and methods disclosed here provide the advantagesassociated with FNA needles of small size and maneuverability, whileoffering a means of collecting more intact samples from target sites.They also are not hampered by the guillotine-style moving parts of othernotched needle systems known in the biopsy art (which are generallylarger in scale due to a need for having a cutting member that movablytransects the notch).

Those of skill in the art will appreciate that embodiments not expresslyillustrated herein may be practiced within the scope of the presentinvention, including that features described herein for differentembodiments may be combined with each other and/or with currently-knownor future-developed technologies while remaining within the scope of theclaims presented here. It is therefore intended that the foregoingdetailed description be regarded as illustrative rather than limiting.And, it should be understood that the following claims, including allequivalents, are intended to define the spirit and scope of thisinvention. In the event of any inconsistent disclosure or definitionfrom the present application conflicting with any document incorporatedby reference, the disclosure or definition herein shall be deemed toprevail.

We claim:
 1. A biopsy needle assembly configured to collect histologicalsamples via a surgical visualization device, the assembly comprising: anelongate notched needle cannula including a distal notch open throughthe elongate notched needle cannula to a longitudinal needle lumen,which longitudinal needle lumen extends through the elongate notchedneedle cannula; and an elongate sheath; where the elongate sheathcomprises a longitudinal sheath lumen through which the elongate notchedneedle cannula is slidably disposed; where the elongate sheath includesa generally cylindrical body defining the longitudinal sheath lumen, thegenerally cylindrical body including: a coiled coated-wire tubeextending proximally from a distal body end, wherein the coiledcoated-wire tube includes a plurality of adjacent coils; a sheathovercoating around the coiled coated-wire tube; and where the coiledcoated-wire tube has an entire proximal end to distal end length with asubstantially consistent outer diameter along that entire length, theelongate notched needle cannula has a substantially consistent outerdiameter along an entire length of the elongate notched needle cannula,and the sheath overcoating includes a first thickness along a distalsheath length, the sheath overcoating includes a second thickness alonga mid-section sheath length, and where the first thickness is greaterthan the second thickness such that the first thickness causes an outerdiameter of the distal sheath length to be larger than an outer diameterof the mid-section sheath length, the sheath overcoating includes athird thickness along a proximal sheath length, and where the thirdthickness is greater than the second thickness such that outer diameterof the proximal sheath length is larger than an outer diameter of themid-section sheath length, wherein the sheath overcoating is in contactwith and extends contiguously between the plurality of adjacent coilsalong the distal sheath length, mid-section sheath length, and along theproximal sheath length.
 2. The assembly of claim 1, where the sheathovercoating comprises nylon.
 3. The assembly of claim 1, where the outerdiameter of the larger-outer diameter distal sheath lengths is about 5%to about 20% greater than the outer diameter of the mid-section sheathlength.
 4. The assembly of claim 1, where a wire that forms the coiledcoated-wire tube is coated with PTFE or another lubricious polymer. 5.The assembly of claim 1, where the elongate notched needle cannulaincludes a beveled distal end tip, and the distal notch is locatedradially opposite and longitudinally proximal of the beveled distal endtip.
 6. The assembly of claim 1, wherein the distal notch is alignedwithin the distal sheath length when a distal end tip of the elongatenotched needle cannula is aligned with or near a distal sheath end. 7.The assembly of claim 1, where the outer diameter of the distal sheathlength is effective to limit endoscope elevator deflection of theelongate sheath to less than deflection allowed by the outer diameter ofthe mid-section sheath length, and the outer diameter of the proximalsheath length is effective to limit device deflection of the elongateproximal sheath to less than deflection allowed by the outer diameter ofthe mid-section sheath length.
 8. The assembly of claim 1, where thedistal sheath length extends about 10 mm to about 50 mm from a distalsheath end.
 9. The assembly of claim 1, further comprising a styletremovably disposed through the longitudinal needle lumen.
 10. Theassembly of claim 1, where the elongate sheath comprises stainless steelwire coated with PTFE and wound to form a consistent-diameter tube. 11.The assembly of claim 1, where the sheath overcoating includes extrudednylon continuously forming the outer diameter of the distal sheathlength, the outer diameter of the mid-section sheath length, the outerdiameter proximal sheath length, and smooth, non-stepped transitionstherebetween.
 12. The assembly of claim 1, where the sheath overcoatingis effective to limit gapping between adjacent coils of the coiledcoated-wire tube during manipulation of the coiled coated-wire tube. 13.The assembly of claim 1, wherein the elongate notched needle cannulaincludes a consistent outer diameter along at least a distal length ofthe elongate notched needle cannula from distal of the distal notch,across the distal notch, and proximal of the distal notch.
 14. Theassembly of claim 1, wherein the elongate notched needle cannulaincludes a pattern of echogenic surface features disposed immediatelyadjacent to and proximal of the distal notch.
 15. The assembly of claim1, wherein the elongate notched needle cannula is configured as a20-gauge needle including an echogenically dimpled surface adjacent thedistal notch.
 16. The assembly of claim 15, where the coiled coated-wiretube of the elongate sheath comprises PTFE-coated stainless steel wireand the sheath overcoating comprises nylon.
 17. A notched aspirationbiopsy needle device, comprising: a flexible elongate tubular cannulasized no larger than 19-gauge, including a cannula wall defining acannula lumen, which cannula lumen is configured to communicate with aproximal source of suction; wherein the cannula lumen extendslongitudinally through the flexible elongate tubular cannula; a distalbeveled end of the flexible elongate tubular cannula including a longside and a short side; a notch through the cannula wall, the notch beingopen to the cannula lumen; wherein the notch is disposed proximallyadjacent to the distal beveled end and is generally centered inlongitudinal alignment with the long side of the distal beveled end andopposite the short side of the distal beveled end; wherein the notchincludes an arcuate cutting edge defined by a distal-facing portion ofthe cannula wall which distal-facing portion of the cannula wall iswithin the circumference of the cannula wall, and extends into thenotch; and an elongate sheath; where the elongate sheath comprises alongitudinal sheath lumen through which the flexible elongate tubularcannula is slidably disposed; where the sheath includes a generallycylindrical body defining the longitudinal sheath lumen, the generallycylindrical body including: a coiled coated-wire tube extendingproximally from a distal body end, wherein the coiled coated-wire tubeincludes a plurality of adjacent coils; a sheath overcoating around thecoiled coated-wire tube; and where the coiled coated-wire tube has asubstantially consistent outer diameter along an entire length of thecoiled coated-wire tube, the flexible elongate tubular cannula has asubstantially consistent outer diameter along an entire length of theflexible elongate tubular cannula, and the sheath overcoating includes afirst thickness along a distal sheath length, the sheath overcoatingincludes a second thickness along a mid-section sheath length, where thefirst thickness is greater than the second thickness such that an outerdiameter of the distal sheath length is larger than an outer diameter ofthe mid-section sheath length, where the sheath overcoating alsoincludes a third thickness along a proximal-most sheath length, wherethe third thickness is greater than the second thickness, such that anouter diameter of the proximal-most sheath length is larger than anouter diameter of the mid-sectional sheath length, wherein the sheathovercoating is in contact with and extends contiguously between theplurality of adjacent coils along the distal sheath length and along theproximal sheath length.
 18. The needle device of claim 17, furthercomprising a stylet disposed through, and occupying substantially anentire cross-sectional area of, at least a lengthwise portion of thecannula lumen, wherein a distal end of the stylet is configured not toextend beyond the distal beveled end of the flexible elongate tubularcannula.
 19. The needle device of claim 17, wherein the flexibleelongate tubular cannula is configured as sufficiently long and flexiblefor passage through a working channel of a peroral surgicalvisualization device to a target site within a patient abdomen.
 20. Theneedle device of claim 17, further comprising a pattern of echogenicsurface features disposed immediately adjacent to and proximal of thenotch.